Conventional telecommunications systems, including wireless communications, perform various audio processing operations during a communications session between one or more users. In particular, such conventional telecommunications systems perform audio processing operations during the alerting interval of the communications session. The alerting interval is generally the period after a first user has placed a call (e.g., dialed or entered a phone number in a telephone device) and the telephone system has signaled the second user's telephone, but before the second user(s) acknowledges or engages the communications session (e.g., answers or picks up his/her phone). Alternatively, the alerting interval may end when a separate process intervenes before the second user(s) acknowledges the communications session (e.g., via an answering machine or voice mail server). Generally then, the altering interval, sometimes referred to as the “ringback” interval or ringback tone time period, is the part of a telephone call in which a calling user hears a ring tone or ringback tone prior to the called user answering the phone, or prior to activation of voice mail or other call transfer.
In conventional telecommunications systems, during the alerting interval, a preprogrammed audio signal, or ringback message, is sent to the user whom initiated the communications session. Typically, the ringback message attempts to mimic or emulate the sound of a traditional telephone ‘ring . . . ring . . . ring’ with varying ring lengths and frequencies to indicate to the calling user that the telephone device of the called user is ringing to alert the called user to answer the phone. Conventional ringback messages may also contain other audio content such as prerecorded speech, music and the like. In some conventional systems, telephone users may customize certain ringback content such that a certain song or voice recording is played for specific incoming callers as designated by the telephone user. For example, caller identification (caller ID) technologies can allow a ringback system to play a specific message to a specific caller while that caller is awaiting the called party to answer the telephone. Ringback messages may be customized according to other various factors such as the time of day or the status of the telephone user (e.g., away on vacation).
During a typical communications session using conventional telephony systems, audio data is propagated, routed and augmented by various in-path equipment located between telephone users. The in-path equipment generally perform voice quality enhancement operations to improve the audio quality of a communications session. Such voice quality enhancement operations typically include, amongst others, noise reduction and echo cancellation processing that is applied to audio signals transmitted over the connection.